Sexual Response Cycle
by eclecticxdetour
Summary: WINCEST of the SamDean Persuasion Rated M for Extreme SLASH Sam and Dean get down and dirty while on a case. This story will follow the psychological sexual response cycle: excitement, plateau, orgasm, and resolution.
1. Excitement

**Warnings**: boy touching, use of endearments, implied and eventual bottom!Sam

* * *

"God, _fuck_, Dean, we _shouldn_--" groaned Sam, eyes rolling to the back of his head when Dean licked at his pulse.

"Oh, we _should_, baby boy," grinned Dean against Sam's slick neck, thumbs flirting along Sammy's hipbones as he feasted on Sam's neck, nibbling at the taut skin as he angled Sam's head to his liking.

"We're on a _case_, Dean," protested Sam, though his actions were definitely _not_ in communication with his thoughts as he arched into Dean's mouth when Dean pulled at the skin where jaw met neck. He felt the muscles of his legs go rigid, glad for it, actually, because if Dean continued sucking at his neck like he wanted to _devour_ him, he was sure his knees would give out soon.

"_Fuck yes_, Dean…" he hissed, face and chest flushing with his arousal. He was half-hard in his jeans and Dean hadn't even _brushed_ against his cock, yet.

"But, Sammy, we're on a _case_," teased Dean in reply, sucking kisses down the column of Sam's neck, thumbs teasing further beneath Sam's waistband.

"Ah, _Dean_, fu-_ck_, you're such a teasing _jerk_," moaned Sam, hips straining against Dean's when Dean's thumbs dipped into the divots of his hips, his second most ticklish spots.

"You love when I tease, baby," answered Dean with a smirk, fingers spanning Sam's lower back and the top curve of Sam's fine little ass.

"Do _not_," hissed Sam petulantly, rocking against Dean's crotch, _finally_ feeling the thick heat of Dean's cock coming to life against him.

He could feel the heat of Dean's own arousal radiating from his big brother, glad that he wasn't the only one affected by their gyrations; amazed that he was able to get Dean hot and bothered, too.

Dean groaned against Sam's mouth, enjoying the feel of Sam hot and hard against him. He felt Sam's soft, warm breaths against his temple as he sucked at Sam's Adam's apple, loved the way Sam's breath hitched when he scraped Sam's skin with his teeth.

He slipped his hands up Sam's shirt, nails gently scratching Sam's belly and torso before his palms found Sam's pectorals. Sam's nipples were hard and erect when he pinched them between thumb and forefinger, much like his own beneath his t-shirt.

He let out a growl when Sam matched his movements, arms sliding between his and smoothing up his t-shirt so that Sam could tease and roll his nipples.

"Fuck, _Sam_," groaned Dean, catching Sam's Adam's apple between his lips and _sucking_ causing Sam to roll his hips into his own. He pressed his forehead to Sam's clavicle and dropped his hands to Sam's waistband, pushing frantically at the button and pushing it through the catch. He pushed Sammy's jeans down around his thighs and cupped Sam's cock through his boxer-briefs, feeling Sam twitch and harden beneath his palm. "You in or what?"

Sam smirked wickedly at Dean and said with a lewd wink, "Oh, I think _you're_ the one that's going to be _in."_


	2. Plateau

**Warnings**: bottom!Sam, wall!sex

* * *

Dean groaned, massaging at Sam's ass through his little brother's underwear, thought of being buried in that tight heat so much more appealing than hunting the monster of the week. He pressed closer to Sam, pushing his baby boy harder against the wall, glad he had some aid to support Sam's long body.

"_Dean_," breathed Sam, feeling his heart beat faster in his chest, breath punching out of him every time Dean rocked against him.

"You want me to, Sammy? Push you up against this wall and fuck you 'till you can't _walk_ much less stand?" he asked of Sam, pushing his hands down the back of Sam's briefs, feeling the hot skin of Sam's ass, pushing and squeezing at the supple flesh.

"Fuck, _Dean_," keened Sam, feeling his aroused blush stain his chest and neck as he got hotter and hotter from Dean's touches. "_Please_," he begged, hating the tone his voice took on when Dean got him like this.

"Alright, Sammy," answered Dean, voice low and gruff. He pushed Sam's boxer-briefs and jeans down below Sam's hips, eyes falling to the jut of Sam's hard cock between his legs. "Jesus," he breathed, curling his fingers around Sam and teasing calloused digits over Sam's length, loving how Sam fit perfectly in his palm.

He smirked at his little brother when Sam's cock jerked and pre-come pooled at the head. "Looks like you're already ready for it, baby," chuckled Dean, thumbing the crown, smearing the pre-ejaculate all around Sam's cockhead.

"Course I am, with you touchin' me like that," moaned Sam, hips pumping into Dean's fist, cock sliding through the delicious curl of Dean's fingers.

Dean nodded and said, "How could you not?"

Sam rolled his eyes even though he knew Dean was right. One fuckin' _look_ from his big brother and he'd be hard and aching in his denims. He grabbed Dean's bicep when his abdomen fluttered, familiar pull of his orgasm heating his belly. "Get on with it," he breathed, shuddering when Dean scratched a blunt fingernail over his frenulum.

Dean grinned and let go of Sammy, peeling Sam from his flannel before he stripped Sam of his t-shirt. "Turn around," he whispered, groaning when Sam did as he'd asked. He eyed the curve of Sam's ass, loving the way it sloped just so from Sam's back. "Sucha nice little ass, baby brother," he growled, couldn't help but give a gentle little slap when Sam flexed.

"_Fuck_," swore Sam, feeling the pulse of his blood in his veins like little bolts of lightning. His heart thundered in his chest, muscles in his arms going tense when he braced himself on the wall. "Do it, Dean," he hissed, gasping when Dean pulled at his hips so he pushed his ass out.

"Gettin' there, Sammy, keep your pan--oh _right_," laughed Dean, pushing Sam's boxer-briefs and pants to his ankles so he'd have more room. He unbuckled his belt and quickly pushed his own pants and underwear down his hips, giving his cock a few strokes until a drop of pre-come beaded at the slit.

"_Dean_," groaned Sam, watching Dean play with himself over his shoulder, hole clenching in his eagerness to get his big brother inside him. He could feel how quickly his chest was rising and falling, like Dean stole every inhale he took with the jerks of his fist.

"You gotta--" and then Dean pressed two fingers against Sam's lips, forehead falling to Sam's shoulder blade when Sam slurped them inside, agile tongue coating his finger with saliva. His cock jerked and leaked between his thighs, feel of Sam's _hotwet_ mouth around his fingers only allowing him to imagine how awesome Sammy was going to feel around his dick. "S'good," he murmured, pulling his fingers out of Sam's mouth before swirling them around Sam's rim.

"_Please,_" begged Sam, pressing back against the teasing pressure of Dean's fingers, heart hammering against his lung and ribcage with how badly he wanted it.

Dean caught his bottom lip between his teeth and pressed his fingers inside, quickly pushing all the way in and gently stretching his fingers. "Goddamn, Sammy," he breathed, curling and crooking his fingers until he found Sam's prostate. "There it is," he said, grin clearly evident in his voice, pleased that he found that spot that would drive Sam insane.

"Fuckin' _Christ_, Dean!" shouted Sam, letting out a pitiful sound when Dean clapped a hand over his mouth.

"Don't need everyone hearin' what we're doin' in here, baby boy," breathed Dean, leaning closer to Sam and licking the shell of Sam's ear. He felt the muscles in his hand spasm, felt the jerk of his balls when Sam clenched around him. "_Jesus_," he groaned, scissoring his fingers inside Sam until Sam let out a pretty little whimper.

"M'ready," breathed Sam, fucking himself back on Dean's fingers, cock smearing pre-come against his belly with every rock of his hips into Dean's manipulations.

"Okay," answered Dean, licking his palm and letting Sam lick it, too, so he could slick himself. He let out a slow breath as he pressed into Sam, blood rushing in his ears, only thing he could hear besides the rapid fluttering of his heart. Jesus Christ, he felt like he was going to implode, breath punching out of him just as quickly as his heart slammed against his ribs.

Sam let out a contented sound when Dean sank balls-deep, hips wriggling as he got reacquainted with the feel of his brother inside him. "God yes," he said quietly, pressing his forehead against the wall when his toes twitched and curled inside his boots.

Dean let out a shaky breath before he carefully pulled out and thrust back in, knowing his cock rode over that spot inside when Sam let out a muffled keen. He curled his arms around Sam's waist, one hand finding Sam's cock as he built up a rhythm, quick pull of his hips before he slowly sank back inside, knew that it tortured Sammy in the best ways possible.

"Oh _fuck_," gasped Sam, feeling his back and chest flushing deeper with his arousal. He swallowed hard, fingers twitching where they were spread against the wall. His entire body shook with every one of Dean's thrusts, toes wildly curling in his shoes, forearms tensing and relaxing when Dean prodded his prostate.

"God, Sam, feel so _good_," groaned Dean, hand spasming around Sam's cock, jerking tenderly at his brother's dick.

Sam could feel his big brother going tense against him, Dean's thrusts becoming more erratic with every pump of his hips into him.

Dean knew Sammy was close, could tell by the flush spreading across Sam's back, deep blush alerting him of Sam's imminent release. He quickened his strokes over Sam's cock, squeezing tighter around Sam as he snapped his hips harder. He knew he was close, too, felt his balls tighten and pull up toward his body, ready to let loose inside his baby brother.

"Dean, m'almost--" cried Sam, forehead thunking against the wall when Dean pressed against his slit, cock riding the bundle of nerves that sent sparks flying through his veins.

"Know, baby, me, too," answered Dean, pressing his mouth to Sam's shoulder as he curled his arm tighter around Sam's waist.

"_Dean_," groaned Sam, feet restless in his boots, toes taking on a mind of their own with how wildly they were curling and straightening.

"_Sammy_..."

"_Dean_, I'm gonna--" yelled Sam, balls tightening between his legs, chest and back flushed, heart hammering in his ears.

"Fuck, _Sam_!"


	3. Orgasm

Dean cried out Sam's name again, feeling like his heart was going to explode out of his chest it was beating so fast. He felt like all his muscles in his body were spasming at once, fingers twitching around Sam's cock, toes curling in his shoes, legs feeling as if he'd run 500 miles.

He pressed his mouth to the back of Sam's neck, feeling the rapid rise and fall of Sam's chest and he knew his brother was about to come. He saw how Sam's fingers went white-knuckled against the wall, the deep sex flush over the entirety of Sam's back and arms and he _knew_ Sam's chest was beet red as well.

Sam felt his balls draw up against his body and he was coming, heart racing in his chest, lungs working a thousand times harder than normal, legs taut as a bowstring, entire body on fire with his orgasm as he came over Dean's fingers. He screamed his big brother's name and felt more than heard Dean groan behind him.

Dean pressed in to the hilt, body shuddering when Sam's muscles clenched wildly around him when his baby found his release, overwhelmed by the amazing pressure around him.

"Goddamn, Sammy," he breathed, stroking Sam through the aftershocks, circling his hips so he could reach his own orgasm.

"Dean, _p-please! _Want it," moaned Sam, slapping his hand on the wall when Dean pulled out and pressed back in, cockhead stroking right over his prostate. "Dean!"

The shout of his name from Sammy's mouth triggered his own release, toes curling tighter in his shoes, muscles at the base of his cock rippling with his release, spilling inside his baby brother as he reached his climax, moaning when his asshole clenched as he came.

"Fuckin'. _Jesus Christ_," he groaned, pumping his hips, feeding Sam's ass the last he had to offer. "Love you, Sammy."

Sam grinned, hole clenching and cock twitching, spurting the last of his jism over Dean's fingers. "Love you, De."


	4. Resolution

Dean let out a slow breath, carefully uncurling his slick fingers from around Sam's dick. He pulled his hand back and licked at his come-sticky fingers when Sam looked back at him, smiling when Sam keened.

"_Dean_," breathed Sam, shifting so he could catch his big brother's mouth, slicking his tongue between Dean's lips so he could catch his taste. He moaned when he caught some of his jizz, swallowing it down before kissing Dean again.

When Dean pulled away he slumped against Sam's back, sweaty and slick from their sexing. He kissed at Sam's nape as he pulled out, cock half-hard and come-slick.

"_God_," groaned Sam, body feeling empty after the stretch of Dean's cock inside. He relaxed back against his brother, heart beat slow and lethargic, mirroring his careful movements as he turned around in the bracket of Dean's arms before slumping against the wall.

Dean smiled and helped Sam back into his pants, dragging Sammy to the floor and pulling Sam to his chest when they sat. He kissed Sam's temple and stroked over Sam's chest, sex flush receding to reveal golden tanned flesh. "Okay?" he asked quietly, thumb rubbing over Sam's flat nipple, smiling when it hardened again beneath his touch.

"Yeah," answered Sam, voice rough from all the noises he had made.

Dean chuckled when Sam's eyes dipped closed, Sam's chest rising and falling in a slow, steady rhythm. "Hey, gotta get back on the case in a little bit, baby boy."

"Know. Just, relax with me for a lil' while, 'kay?"

He could feel how limp his muscles were, how relaxed his entire body was and he agreed. He turned Sam's face toward his own and kissed Sam before he said, "Alright," and he pulled Sam a little closer and snuggled against Sammy's back, grinning when Sam's hand settled over his own.


End file.
